It is known in the art that along the path of power grids there are provided various electrical devices, such as fault-protecting devices, monitoring devices et cetera. As a whole, such electrical devices, which can be grouped into substations, are devoted to ensure that electric power is transmitted and distributed properly and correctly to loads and users, preventing the occurrence—or intervening in case—of electrical malfunctioning or faults.
To this end, in recent years some compact and multifunctional switchgear have been designed, which integrate in a unique apparatus and are able to perform several electrical functions; some examples of such kind of multifunctional switchgear are disclosed in U.S. Pat. No. 5,796,060 and European Patent No. EP1121739.
Such devices can include a main casing which houses one or more electrical devices; e.g., a disconnector, a circuit breaker, current and/or voltage transformers, et cetera.
On top of the casing there are mounted one or more bushings each containing a corresponding electric conductor so as to realize an input or output connection of the switchgear with the outside; e.g., with a power line and/or with other electrical components of the substation.
One issue of these devices resides in the fact that, once assembled in the manufacturing plant, their overall size (e.g., their height), may exceed the maximum standards for shipping (e.g., road shipping).
Indeed, it is often necessary to ship poles of the device separately, or to adopt shipping configurations rather complicated, or even to disassemble parts, such as the bushings from the casing, and to reassemble them at the installation site. This latter solution clearly entails additional issues, for instance re-conditioning and/or re-testing the equipment, especially if the switchgear contains an insulating gas, or if air, dust, et cetera, penetrate inside it.